media: lirc_zilog: Clean up lirc zilog error codes

According the coding style guidelines, the ENOSYS error code must be
returned in case of a non existent system call. This code has been
replaced with the ENOTTY error code indicating a missing functionality.

Signed-off-by: Yves Lemée <yves.lemee.kernel@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>